Total daily energy expenditure is the number of calories a person burns over 24 hours. Eating about that many calories maintains weight; eating less or more leads to loss or gain over time. The National Academies' 2023 Dietary Reference Intakes for Energy break it into three parts: resting energy expenditure, which typically accounts for 60 to 70 percent; the thermic effect of food (the energy used to digest and process meals), about 10 percent; and physical activity, the most variable part, ranging from 15 to 50 percent depending on how active a person is.
Formula
A common estimate multiplies basal metabolic rate by an activity factor:
TDEE ≈ BMR × PAL
- BMR: basal (or resting) energy expenditure in kcal/day, often from the Mifflin-St Jeor equation.
- PAL: physical activity level, the ratio of total to basal energy expenditure.
The 2023 report groups PAL into four ranges: inactive 1.0–1.53, low active 1.53–1.68, active 1.68–1.85 and very active 1.85–2.50. Calculators use similar multipliers, though exact values vary by tool.
Example
A 40-year-old man who weighs 80 kg and is 180 cm tall has a Mifflin-St Jeor BMR of 1,730 kcal/day. With a low-active lifestyle (PAL 1.6):
- TDEE ≈ 1,730 × 1.6 = 2,768 kcal/day
Across the whole low-active range (1.53 to 1.68) the estimate runs from about 2,647 to 2,906 kcal/day, which shows how much the activity choice drives the result.
The macro calculator estimates TDEE and turns it into gram targets, and the guide to calculating macros explains each step. Splitting those calories among protein, carbohydrate and fat is guided by the Acceptable Macronutrient Distribution Range.
Common mistakes
- Overstating activity. Choosing a higher category than daily life supports is the easiest way to overestimate TDEE.
- Counting exercise twice by adding tracked workout calories on top of an activity factor that already includes them.
- Treating the estimate as fixed. TDEE changes with body weight and activity, so it should be recalculated after significant changes.